I'd be curious to know just how good this data is. The original link posted here indicates that the data is generated from aerial photos so I would assume that in areas with a lot of tree cover the data is poor to non-existent. Can anyone verify this?

I've been looking at the data and comparing it with open street map footprints and with places I'm familiar with. In general, the Microsoft data simplifies the buildings a bit. So a building with lots of little ins-and-outs will be simplified to a straighter shape. You wouldn't want to use the footprints for a sprint map without field checking.

Of course, the photos can be out of date. There's an area of my town where a bunch of buildings were demolished. They show up on the Microsoft data, but I'd removed them from OSM soon after they were demolished.

The big advantage of the Microsoft footprint data is that it has such good coverage. There are lots of places on OSM where the road network is shown but not much else. Having the building footprints adds a lot of detail.

The first couple of spots I checked (here in rural, forested New England) were missing some buildings. Also, for both my town and the town where grew up, they show the old high school buildings (now demolished) rather than the new ones that have been there for a couple of years. But I still consider this quite good.